On Tue, 16 Jun 2009 20:04:14 -0400, "mazorj" <mazorj@xxxxxx>
wrote:
Quote:
> In Vista 64 home premium SP1, in running chkdsk for C: at the end
> it states that there are 85,144,492 "total allocation units on disk"
> but the next line says there are 187,552 "allocation units
> available on disk". No disk errors were found.
>
> 1. What are allocation units and why are they there?
Space is allocated on the disk in units called "clusters" or
"allocation units." If your drive is NTFS, the default size of
allocation units is 4KB.
So if you have a file that's exactly 40KB in size. It uses 10
allocation units. If the file is 40KB plus one byte in size, it will
use 11 allocation units.
You apparently have a drive that's about 350GB in size. I got that
number by multiplying 85,144,492 by 4096. If you have 4K allocation
units the statements "you have 85,144,492 allocation units" and "you
have a 350GB drive" are equivalent.
Quote:
> 2. Does this mean I'm running out of allocation units?
No, not really. It means you are running out of disk space.
Quote:
> If 187,552 represents 0.22% of the 85,144,492, then are
> 99.78% of the total allocation units on the disk already
> in use and therefore not available for writing new files
> in the directories?
You are running out of disk space.
Quote:
> 3. Will I hit some kind of brick wall here?
You are running out of disk space.
Quote:
> If so, is there some way to free up allocation units before
> that happens?
If you delete files you don't need, or make some of them smaller, you
will use less disk space and therefore fewer allocation units.
--
Ken Blake, Microsoft MVP - Windows Desktop Experience
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